1. Field of the Invention
The present invention relates to a washing method for washing various types of parts including optical components such as lenses, mirrors and the like, and substrates used in optical/magnetic memory disks and the like, and specifically relates to a washing method for washing an object to be washed using an nonaqueous solution.
2. Description of the Related Art
Conventionally, when producing various types of components and optical elements such as lenses and the like, these components are washed to remove grease and debris adhered to the component during processing. Conventionally, chlorofluorocarbon solvent is widely used for washing such components, but its use is regulated due to problems of environmental pollution, and other solvents such as tetrachloroethylene and methylene chloride and the like are also being regulated due to concerns of environmental pollution.
For this reason in recent years washing methods are used wherein, after removing greasy stains such as cutting oils and pitch adhered to the object to be washed using a nonaqueous solution of hydrocarbon solvents and the like, the object to be washed is washed in an aqueous solution using an emulsifier or the like to remove the nonaqueous solution adhered to the object to be washed, and thereafter the object to be washed is finish washed using city water and pure water.
On the other hand, when the object to be washed is washed in an aqueous solution using an emulsifier or the like after the object to be washed has been washed using a nonaqueous solution, the aqueous solution is rapidly contaminated by an abundance of the nonaqueous solution introduced into the aqueous solution, such that the problem arises that the object to be washed cannot be suitably washed in the aqueous solution, and, therefore, the aqueous solution using an emulsifier must soon be replaced, which causes the further problems of lower work efficiency and higher running cost.